Revision as of 03:39, 25 February 2016

This page lists the allowed extension values for the name="" attribute of the <meta> element in HTML5.

You may add your own values to this list, which makes them legal HTML5 metadata names.

We ask that you:

avoid redundancy - if someone has already defined a name that does roughly what you want, please reuse it.

be sure to include all the itemsrequired by the specincluding a link to a specification that specifies the keyword as an HTML meta keyword. If a proposal lacks a specification and a version in a complete specification exists, the latter is to be preferred.

Note that URL-valued properties must not be registered as meta names but should be registered as rel keywords instead.

Also note that changes to this registry will not be reflected in validators in real time. But the validators will get automatically updated with the changes within one week or so.

For Windows 7: "[D]efines the name of the Pinned site application instance. This is the name that appears in a tooltip when hovering over the Pinned site button on the Windows 7 taskbar. The application name is also appended to the window title of the Pinned site application instance." Although the documentation refers to an application, it gives an example of writing this metadata for HTML.

Used to identify users for JokeNetwork's Blazerr Support-System along with a cookie. The verification of a user without the use of cookies can be obtained with the deprecated meta tag blazerr-support-id-noncookies.

Checks whether Blazerr SEO has been used or not. It contains the user-id and the SEO Version.

Usage: <meta name="blazerr-seo" content="0001;v0.7">0001 is an example for a user id, v0.7 identifies which version of SEO is used (In this case version Beta 7 / 0.7). If you're using Blazerr SEO, you have to include this meta-tag. Otherwise the tool will not work.

To replace the obsolete dc:collection. A collection is described as a group, an aggregation of topics Used to describe the top-level content of XHTML documents. These appear in your META tags showing a group of subject. Website Taxonomy improve classification for search engine analysis and semantic communication with a description language content.

Defines the vendor's contact information by way of a phone-number (such as the customer support number), an e-mail ID (such as the customer support mail ID) or a physical address (such as the office address or billing address).

Usage: <meta name="contact" content="+1-555-555-5555 abc@xyz.com '5844 South Oak Street, Chicago, Illinois'">or in case of multiple entries:<meta name="contact" content="Chicago: +1-555-555-5555 abc@xyz.com '5844 South Oak Street, Chicago, Illinois'; Brookfield: +1-444-444-4444 def@xyz.com '2341 Cherry Lane, Brookfield, Illinois'">
The content attribute is a space separated string containing the phone-number followed by the e-mail ID and then the address (specified within quotes).
For specifying multiple entries a semi-colon separated list of name: value pairs can be defined. The name can be any descriptive tag identifying the given location.Valid phone numbers and mail IDs should be provided by the vendor. The address can either be a string specified within quotes or the latitude and longtitude coordinates.

Used by the Detectify web vulnerability scanner as a domain verification key. The Detectify service will only consider the domain authenticated if it contains the "detectify-verification" meta tag, with the content set according to a per-customer token.

A point or period of time associated with an event in the lifecycle of the resource represented in terms of ICAS long date format such as "UCN 12012 M03 Blue ❀ day 333 ❀ IDC zone(UT) t969 tt189". example <meta name="icas.datetime.long" content="UCN 12012 M03 Blue ❀ day 333 ❀ IDC zone(UT) t969 tt189"/>

a preliminary specification in the aaticas group on LinkedIn (http://www.linkedin.com/groups/aaticas-4034149). after a period of review, a specification for AAT ICAS meta keywords for HTML(5) will be referenced on an AAT ICAS area of the aatideas.org web site.

proposal

icas.datetime.day

A point or period of time associated with an event in the lifecycle of the resource represented in terms of ICAS day-of-year format such as "2012 day 333 t969".

a preliminary specification in the aaticas group on LinkedIn (http://www.linkedin.com/groups/aaticas-4034149). after a period of review, a specification for AAT ICAS meta keywords for HTML(5) will be referenced on an AAT ICAS area of the aatideas.org web site.

proposal

icas.datetime.abbr

A point or period of time associated with an event in the lifecycle of the resource represented in terms of an ICAS abbreviated format such as "d2M03 t969".

a preliminary specification in the aaticas group on LinkedIn (http://www.linkedin.com/groups/aaticas-4034149). after a period of review, a specification for AAT ICAS meta keywords for HTML(5) will be referenced on an AAT ICAS area of the aatideas.org web site.

proposal

icas.datetime

A point or period of time associated with an event in the lifecycle of the resource represented in terms of an ICAS date and time format of unspecified information density (may include full, long, medium, short, or compressed forms).

a preliminary specification in the aaticas group on LinkedIn (http://www.linkedin.com/groups/aaticas-4034149). after a period of review, a specification for AAT ICAS meta keywords for HTML(5) will be referenced on an AAT ICAS area of the aatideas.org web site.

proposal

format-detection

Enables or disables automatic detection of possible phone numbers in a webpage in Safari on iOS.

National subdivision (state, canton, region, province, prefecture) of civil address to which the page is related. For resources within the US and Canada, corresponds to the common 2-character State/Province codes.

Used to declare text that should not be translated by the Google Translate plugin (<meta name="google" value="notranslate"> will declare the whole page should not be translated, while <span class="notranslate"> is for text or paragraph areas you wish to not be translated.

Used "[t]o tell Google not to show a Sitelinks search box when your site appears in the search results" (implement with content="nositelinkssearchbox") (already in use).

Presumably, multiple meta elements named "google" should all be parsed but this is may not have been explicitly specified anywhere.

If set to "true", disables Internet Explorer 11 Reading View button adjacent to address bar when the page is detected to have content suitable for Reading View. This is intended for pages that are not articles and are not intended to be read in IE 11 Reading View.

Specifies the cryptocurrency address (bitcoin, etc.) for sending tips to the people responsible for creating this page's content. This tag is used by various browser plugins that want to compensate the site's creators. Since it's microtipping instead of micropayments, there is no need to specify an amount.

Specifies the mobile-compatible url of the web page. Used by mobile browsers and search engines to redirect mobile phone visitors to the proper mobile page.

The following properties can be used in the value of the content attribute:url - The mobile-compatible url of the web page.format - The format of the mobile page. An enum of "wml", "xhtml" and "html5".Example:

The "msapplication-starturl" metadata contains the root URL of the application. The start URL can be fully qualified, or relative to the current document. Only HTTP and HTTPS protocols are allowed. If this element is missing, the address of the current page is used instead.

Jump List items act as entry points into the website even when the browser is not running. A Jump List can contain commonly used destinations and tasks. Some items apply to the whole site, and some apply only to specific users.
For example, to add a single task called "Check Order Status" specify a meta element in the head of your webpage, as follows:

The "msapplication-window" metadata sets the initial size of the Pinned Site window when it is launched for the first time. However, if the user adjusts the size of the window, the Pinned Site retains the new dimensions when it is launched again.
The following properties can be used in the value of the content attribute:

The "msapplication-config" metadata defines the path to a browser configuration file, letting you set pinned sites customizations (such as tile background, badge updates and notifications) with this external XML file rather than metadata within the HTML markup of webpages.

<meta name="msapplication-config" content="IEconfig.xml" />

Note
Without this metadata, IE11 looks for a default "browserconfig.xml" in the root directory of the server.

The "msapplication-TileColor" metadata define the background color of a tile in Pinned Sites in Windows 8. The tile color can be specified as a hex RGB color using CSS’s #rrggbb notation, via CSS color names, or by the CSS rgb() function.

Used by Pingdom monitoring services as a heartbeat verification. The heartbeat service will only consider the request successful if it contains the "pingdom" meta tag, with the content set according to a per-customer key.

The Restricted to Adults label (RTA) provides a way for adult oriented websites to indicate that their content is off limits to children. RTA was introduced in 2006 and is currently used by a large number of adult web content providers. RTA is recognized by all major parental control filters.

revisit-after is used to tell search engines how often to recrawl the page. To our knowledge only one search engine has ever supported it, and that search engine was never widely used — at this point, it is nothing more than a good luck charm.

The purpose is to enable search engines and other cataloging services to compile the types of rights allocated to the work. (Does any search engine actually implement this? hsivonen 07:34, 14 July 2011 (UTC))

This keyword does not provide, remove or alter any legal protections or designations.

A comma-separated list of operators explaining how search engine crawlers should treat the content. Possible values are "noarchive" to prevent cached versions, "noindex" to prevent indexing, and "nofollow" works as the link rel value with the same name. This meta name is already supported by every popular search engine.The content value "NOODP" has been offered elsewhere, so I'm proposing it here. It blocks robots from using Open Directory Project descriptions of a website instead of Web pages' own meta descriptions. It may have been introduced by Microsoft.The content value "NOYDIR" has been offered by Yahoo, so I'm proposing it here. It blocks Yahoo's robot from using the Yahoo directory's descriptions of a website instead of Web pages' own meta descriptions. Whether any other robot supports this is unknown but possibly no other search engine uses Yahoo's directory anyway.

Prevents the Skype browser extension from automatically seeking through the page and replacing telephone numbers (or any number the program's algorithm thinks is a telephone number) with its own custom presentation that allows direct invocation of the Skype program to call the telephone number.

(Note: This violates HTML5, section 4.2.5.2, which says this, because the value is a URL, must be a link element and not a meta element, but Google already recommends and parses this as a meta element.)

Provides a way for documents to specify (using markup rather than CSS) the size, zoom factor, and orientation of the viewport that is used as the base for the document's initial containing block. The following properties can be used in the value of the content attribute:

Used to configure the appropriate Webtrends advanced feature. These are just some of the more popular ones. These appear in your META tags. – showing you the web page, the source (meta tag), the log files entry and the subsequent WT report.
Example:

Used to configure the appropriate Webtrends advanced feature. These are just some of the more popular ones. These appear in your META tags. – showing you the web page, the source (meta tag), the log files entry and the subsequent WT report.
Example:

This defines a scenario step name for the page or set of pages to be included in the scenario. This in turn produces a funnel type report in Webtrends. It works when paired with metedata tag name WT.si_n.
Example:

This defines a scenario step number for the page or set of pages to be included in the scenario. This in turn produces a funnel type report in Webtrends. It works when paired with metedata tag name WT.si_n, and as an alternative to Wt.si_p.
Example:

This defines an error code web page so that Webtrends can identify it as a non-success page. Generally used to identify pages that contain 400 and 500 series return codes. As a result, Webtrends excludes these pages from its standard "Pages" report, to instead populate its standard "errors" report.
Example:

When a visitor to your site clicks on an ad, that action is referred to as an Ad Click. The following META tag tracks advertising clicks:

<META NAME="WT.ac" CONTENT="name">

Defines the name of the advertisement clicked to reach a particular web page. The Ad Click must contain an external redirect back to the client. The redirect needs to include the necessary code to generate a hit to the SDC server. You can designate multiple Advertising Clicks using semicolons.
Examples:

The name of the advertisement clicked to reach a particular web page. To capture this information with DCS, the Advertising Click must contain an external redirect back to the client. The redirect needs to

include the necessary code to generate a hit to the DCS. The maximum length for each name is 64 bytes.

Visitors often view advertisements that they do not necessarily click on. You can use On-Site Advertising to determine the number of visitors to your web site who view particular ads. With this feature you can produce advertising reports for each of your clients.
If you are selling advertising space on your web site, for example, you can collect traffic statistics to help determine pricing schedules.
The following META tag tracks advertising views:

<meta name="WT.ad" content="My content">

An Ad View occurs when a visitor views a page containing an ad. An ad is a link or graphic that contains an Ad Click parameter in the query portion of it's URL.

To attract new students, a university launches a marketing campaign by sending recruitment email to all graduating high school seniors in a metropolitan area. The email links to a special landing page in the university’s web site, containing the following META tag to track marketing campaigns.
Example:

If your site is hosted on multiple servers, a server cluster, or a server farm, and you want to evaluate the performance of your load balancer, Webtrends can track page views for each server. To do so, populate the following META tag on all pages on each server:
Example:

<meta name="WT.sv" content="My Server">

Defines the name of the machine that serves the web page. If you have two servers (Server1 and Server2), you would make two copies of the META tag and designate CONTENT=“Server1” for deployment to pages on the first server and CONTENT=“Server2” for deployment to the same pages on the second server.
For a server farm, you can extract the value of the built-in server name and dynamically assign it to the
META tag using server-side scripting.
Example:

You may want to modify a page title before sending it to Webtrends in the following cases:

You are dealing with dynamic content pages identified by URL parameters, and the page title represents the title of the base URL page rather than the dynamic content page.

Unless you modify the page titles, all pages have the same title in the reports.

All pages have been assigned the same title, for reasons of style or company policy.

Even though URLs are displayed in addition to page title, the entire URL cannot be depended upon to distinguish one page from another.
Use server-side scripts to change the title to something that reflects the content of the pages so that you can identify them in reports. Next, pass the customized page titles to Webtrends, using the following META tag:

The spec specifies this to be a value of the property attribute--not a meta keyword

audience

To aid search engines in classifying and to aid directory compilers, an audience most appropriate for the page may be suggested. Subject matter may not be a good clue; for example, an analysis of children's literature may be directed to teachers.A value is free-form case-insensitive text without a comma. Multiple values are to be comma-separated. Singular and plural forms have the same meaning.Recognized values:-- "all" and "everyone", which have the same meaning-- "adult" and "mature" have the same meaning and are for content that only adults may access, but no one responsible for preventing a nonadult or the immature from accessing the page or its content should rely on either or both of these values to do so without other means (not the same as "grownup", which see)-- "child" and "juvenile", which have the same meaning-- "teen"-- "grownup" is not identical to "adult" or "mature" in not implying a precise boundary but is approximately any person who may be able to understand and apply the content (e.g., car driving instruction that may be read by a minor not yet old enough to drive a car but who would likely benefit from somewhat early exposure to the instruction)-- "parent" to include guardian and temporary caregiver-- "teacher" to include professor and ad hoc instructor-- "elementary school student" to include any student below high school-- "high school student"-- "elhi" to include any student in elementary school through high school-- "college student" including graduate and professional school-- "business" including management, finance, and prospective customers (this includes e-commerce and investor sites)-- "health" including any health care provider including alternative and ad hoc-- "patient" for any health care recipient-- "lawyer" including judge, paralegal, and jailhouse lawyer-- "law client" for any prospective recipient of a lawyer's service (not usually a social work client) with lawyer including paralegal and jailhouse lawyer but not necessarily judge-- "craft" for any craftworker including laborer and artisan-- "artist" including musician, actor, dancer, and sculptor and including creator and performer-- "military" including paramilitary-- "news" including any consumer of rapidly-developing news-- "introductory" and "beginner", which have the same meaning-- "intermediate" and "midlevel", which have the same meaning-- "advanced" and "advance", which have the same meaning-- "scholarly" and "scholar", which have the same meaning-- "popular" generally referring to a writing style-- "older" including retiree-- "institution" including from corporation to conspiracy (such as for management advice)-- "government" including agencies and prospective politicians-- values using any integer or single-digit decimal in the form of "grade 8" or "grade 6.4" including to refer to a reading comprehension level (this generally will not exceed 12 and might be meaningless above 20 so higher values may be interpreted as the highest meaningful value)-- "viewers" for when content (such as a movie) is intended almost entirely to be seen rather than read-- "listeners" for when content (such as music) is intended almost entirely to be heard rather than read but not generally including text-to-speech support-- "tts", "text-to-speech", or "text to speech", which three have the same meaning and which are for a page that has substantial support for TTS or that will be readily understood through TTS without need for such support (TTS is often aided by, e.g., pre-resolving pronunciation ambiguities in page coding)-- values using any numbers in the form of "3-6 years old", whether a range or a single-number value-- values using any decade in the form of "born in 1970s"Unrecognized values such as "botanists", "Texans", and "writers who use red ink" may be used but at a risk that a search engine or directory editor will either fail to recognize it or will interpret it in unpredictable ways, or will in the future.Spellings that are erroneous or slightly different from a recognized value may be interpreted by a search engine or directory editor as representing a recognized value.The absence of the keyword defaults to a value of "all" but without overriding another indication arrived at by other means.

Robot owners, to allow page authors access to robotic capabilities, e.g., to deny them, should prefix "bot-" to the name of their robot, especially for proprietary bots.Example: If a robot were to be named "dullbucklequiz", the name in the meta element would be "bot-dullbucklequiz".The value "bot-" alone represents all bots so prefixed, like a wildcard.Arguably, there's no need for a list here of any specific bots if http://user-agents.org or http://www.botsvsbrowsers.com/ (and perhaps other sites) is reliable.

Incomplete proposal

Lacks link to a spec, tries to register a space of names instead of enumerated names

created

The datetime at which the document was created. The value is an ISO8601 date. The date MUST follow the W3C Profile of ISO 8601 with a granularity of "Complete date:" or finer. The BBC use this name.

Incomplete proposal

Lacks link to a spec

creator

The creator is an off-Web or pre-Web creator of a work for which an author authored a Web page, so that the creator and the author may be different people.Searching for one content creator's work requires a standard robot-parsable format for the information. A personal name, institutional name, or other text entry is permissible.One element represents only one creator. Multiple creators are to be represented with multiple tags.Search engines may index by any component of a name, so a content creator need only enter a name once in one first-last or family-given order (e.g., Pat Thunderbird or Thunderbird, Pat, but not requiring both).

The author may be the best expert on which time frame is most relevant to the content. Leaving that to search engine analysis may be too chancy without search engine optimization, which analysis is difficult to apply by algorithm to, e.g., historical papers that may focus on the 1800s but mention 1731 and 1912 perhaps unimportantly.The value for this keyword is a date or time -- not a range and not vague, for which other keywords are proposed -- in a format in accordance with http://www.w3.org/TR/NOTE-datetime (albeit a note that's at W3C only for discussion). Any of the six levels of granularity in that note are acceptable, such as expressing only a year.Should this keyword appear more than once, all the values so appearing are determinative. Multiple values are to be expressed with separate meta elements lest the note be revised in the future in a way incompatible with comma-separating a list.

Incomplete proposal

Lacks link to a spec

property="og:*"

Metadata used by the Open Graph protocol (used by Facebook). Note: currently these are defined as: <meta property="og.*" content="x"/>

This is identical to the keyword datetime-coverage except that it represents only the end. If this keyword is used without datetime-coverage-start (also proposed), its value is interpreted as ending a range without a start.Should this keyword appear more than once, all the values so appearing are determinative, in which case each represents the end of a different range assumed to be nonnesting. Example: If four elements happen to be in the order of datetime-coverage-end=1865, datetime-coverage-start=1914, datetime-coverage-end=1918, and datetime-coverage-start=1862, assuming proper formatting, the ranges should be interpreted as 1862-1865 and 1914-1918.

Incomplete proposal

Lacks link to a spec

datetime-coverage-start

This is identical to the keyword datetime-coverage except that it represents only the start. If this keyword is used without datetime-coverage-end (also proposed), its value is interpreted as starting a range without an end.Should this keyword appear more than once, all the values so appearing are determinative, in which case each represents the start of a different range assumed to be nonnesting. Example: If four elements happen to be in the order of datetime-coverage-start=1862, datetime-coverage-start=1914, datetime-coverage-end=1865, and datetime-coverage-end=1918, assuming proper formatting, the ranges should be interpreted as 1862-1865 and 1914-1918.

Incomplete proposal

Lacks link to a spec

datetime-coverage-vague

This is identical to the keyword datetime-coverage except that its value is not necessarily crisp. This keyword should be used only when datetime-coverage, datetime-coverage-start, and datetime-coverage-end are inappropriate, but there's no ban on using all four. Any text without a comma can be the value (e.g., Pleistocene, 1820s, Tuesdays, or before we were born); multiple values are comma-separated.If this keyword is used with datetime-coverage, datetime-coverage-start, or datetime-coverage-end, the vague value should be exploited along with the value/s for the other keyword/s.Should this keyword appear more than once, all are determinative.

Incomplete proposal

Lacks link to a spec

DC.

Dublin Core, maintained by Dublin Core MetaData Initiative (DCMI), is an extensive system with some overlap with non-DC names.This reserves all strings that begin with DC and a dot. Not true; DC-HTML doesn't use hardwired prefixes, but defines the prefixes using link/@rel="scheme.prefix"

When several pages in a directory include main content, a table of contents, an index, and the like, a search engine may be able to organize results more usefully by identifying which is which with a standard vocabulary, helpful when different publishers use different conventions when displaying or printing content.A value is free-form case-insensitive text without a comma and optionally with a trailing number. Multiple values are to be comma-separated (multiple values are appropriate when one document serves multiple purposes). Singular and plural forms have the same meaning.Recognized values, which are pointer types to which numbers may be suffixed, are limited to "start" meaning 'the first page that should be seen by a user' (this may be anywhere in the directory and anywhere within content), "toc" meaning 'table of contents', "intro" including introductions, forewords, prefaces, and tables of figures, "abstract", "main", "bibliography" and "biblio", which have the same meaning, "index" which may mean 'sitemap' or not, "afterword" and "update" which have the same meaning and need not actually update, "credit" meaning 'credits and acknowledgments', and "author bio" meaning 'author's biography', including any information about the author including credentials and contact information. The number suffix may be spaceless or not.When numbers are suffixed, a search engine or directory should arrange like items in numerical order in the results, with unnumbered items following like items that are numbered, e.g., intro 1, intro 2, main 1, main 2, main, main, and so on.Each directory and each subdirectory has its own sequence.

Incomplete proposal

Lacks link to a spec

expires

meta name='expires' defines the expiration date of the page. This can be used for web pages in preparation for an upcoming event, e.g. a registration form for an exposition or competition, or other cases with a pre-set date when the document will no longer be valid, e.g. a product offer in a special sale or a support page for a product known not to be supported anymore from a given time onward.

Search engines should respond to this meta tag in a reasonable way, i.e. by removing the page from their main search results after the expiration date (possibly still returning the result in a special search for expired pages as long as the page exists and is not explicitly excluded via robots.txt or meta name='robots' etc.) or simply by indicating to the user that this result is out-of-date.

The content attribute should define the expiration date in accordance with http://www.w3.org/TR/NOTE-datetime . The meta tag should not be used for pages without expiration date. However, for historical reasons, search engines should also interpret other date formats where possible and should be prepared to find values such as "", "0", "no" and "never". Such non-date values are to be interpreted as no expiration date.

Correctly formatted example:

<meta name='expires' content='2012-12-31T23:59Z'>

This tag is not to be confused with and has a different meaning than meta http-equiv='expires'.

Incomplete proposal

Lacks link to a spec

format-print

This is to allow a user agent to inform an operating system or a printer driver of the preferred print medium, such as the paper size.A value is free-form case-insensitive text without a comma. Multiple values are to be comma-separated (multiple values might be appropriate because standard paper sizes vary around the world). Singular and plural forms have the same meaning.Recognized values are limited to "letter", "A4", "legal", "A5", "B5", "monarch", "envelope 10" meaning size #10, "envelope 6-3-4" meaning size #6 3/4, values with integers and decimals in the form of "8.5 x 11" or "8.5x11" in which spacing of the "x" does not affect meaning, "paper", which means 'paper of the default color (usually white) and weight (usually 20-lb. stock)', "white", "yellow", "pink", "blue", "green", "violet", or "multicolor", which means a medium of the given color or mixed, "letterhead", "p2 letterhead" meaning 'letterhead intended for any page except the first', "watermark" meaning a 'special watermark such as an organization's own', and "plain" meaning 'not preprinted and not letterhead (it may have a paper manufacturer's watermark not related to letterhead)'.Omitting "paper" when another recognized value is given defaults to an implied meaning of 'paper' with the other value; e.g., "letter" means 'letter paper'; the same principle applies to a medium's color (the default being white for paper and colorless for transparency) and plainness or lack thereof (the default being plain).Other values should be proposed before being recognized here. Label sizes should be proposed here for labels that are not on backing sheets that fit one of the recognized values, e.g., labels on narrow rolls. Blueprint paper sizes should be proposed here. Media other than standard paper, such as onion skin, heavier paper, card, and clear or color transparency, should be proposed here.The user agent may, with the user's or user sysadmin's permission (as by a menu-driven default), interpret a value to offer an alternative the user might accept and software and firmware other than the UA may interpret a value to the same end with or without permission, so this keyword is only suggestive; e.g., "letter" may be interpreted as "A4".The absence of the keyword defaults to a value determined by other than the page, e.g., by the printer driver or the user agent.

The author may be the best expert on the geographic relevance of the content. Leaving that to search engine analysis may be too chancy without search engine optimization, which analysis is difficult to apply by algorithm to, e.g., historical papers and epidemiological studies which may mention locales only once.Absence of the keyword defaults to a value of world (not universe), unless the search engine chooses to interpret the page or larger unit for some other value, probably based on other than just contact information given in the website.The value for this keyword is a semicolon-separated list of one or more place-values, the order of which do not matter. One place-value will use commas to separate, in order, an optional standard natural language symbol applicable to the place-value (when omitted the language applicable to the page will control), a place-class, one or more place-subclasses if any, and one or more place name parts (where, e.g., in "Cape Town, South Africa", "Cape Town" is a place name part but "Town" is not). Spaces after semicolons and commas are optional; spaces within place-values are present when required for each place-value (e.g., "Quezon City", not an invented "QuezonCity").To distinguish names that might otherwise be too similar, place-classes, all lower-case and hyphenatably spaceless, include outer-space, region (on Earth and crossing or larger than a nation, e.g., southern hemisphere, polar region, temperate zone, or Asia), intntl-water (an 'international water body'), intntl-agcy ('international agency' or 'international collection', e.g., all U.N. member nations), nation, within-nation (limited to only one political level down from nation, e.g., state, province, territory, possession, city not included within other political units of a nation, or any comparable unit), city (including town, village, hamlet, and any comparable political unit below the level of within-nation), addr (including address, full-length street, building, institution, and neighborhood without political boundaries), pol-unit (pol abbreviating 'political') (e.g., a place of disputed nationhood), hist-pol-unit (hist abbreviating 'historical') (e.g., the Roman Empire), feature (e.g., river), num (e.g., latitude and longitude or outer-space equivalent in numbers), and ethereal (including thealogical/theological, fictional including from modern popular entertainment, and ancient secular mythical, but not including that which is asserted to be a state of mind or existence but not a place, such as nirvana). (Example for one hypothetical page: name="geographic-coverage" content="region, sub-Saharan Africa; nation, Panama; city, Panama, Panama; within-nation, Sao Paulo, Brazil; city, Sao Paulo, Sao Paulo, Brazil; within-nation, Mississippi, United States of America; region, Middle East; region, Midwest, United States of America; hist-pol-unit, Northwest Territory, United States of America; feature, river, Indus; outer-space, Indus; ethereal, ultima Thule; ethereal, Heaven; ethereal, Flatland; ethereal, Valhalla; en-US, addr, Hotel Valhalla, Fredrikstad, Norway; es, nation, Espana" (Indus is both a river and a constellation, illustrating the need for place-classes)).Ambiguity of place-values should be avoided despite convenience in coding because search engines may each interpret them as they see fit, e.g., it would be hard for an engine to distinguish New York from New York.For consistency of spelling, several authority lists should be settled upon, with legal, well-known, and disputed names and common abbreviations all being acceptable; but I'm not proposing one here now (relying on IANA's ccTLD list might be too complex to implement and still assure coding consistency, e.g., occasionally ccTLDs can be phased out and off of IANA's list) (a standard vocabulary possibly usable here is the Getty Thesaurus of Geographic Names Online, subject to licensing and charset choice); and promulgating authority lists may best be done publicly by search engine managements, who may disagree with each other.Allowing Unicode for non-Roman alphabet-using locales is desirable, but at present that may raise technical problems, including computer security issues, that are not yet readily soluble.

A comma-separated list of negative keywords that distinguish a closely-related theme from this page's true theme, to support Boolean NOT searches often more realistically than visible text can, especially when both themes share the same lexicon.If keywords is no longer a supported name for a meta element, keywords-not is superfluous; however, debate has been revived on whether keywords should be supported or not; see the keywords entry in this Wiki.

Better ranking in search engine results for recency or relevance to an event date would be aided by a standard format robots can parse. Users would save search time by not having to load many pages to find which ones are new or date-relevant.To supply a consistent and known format, the value for this keyword is a date-time expression formed in accordance with http://www.w3.org/TR/NOTE-datetime (albeit a note that's at W3C only for discussion). Any of the six levels of granularity in that note are acceptable, such as expressing only a year.Should this keyword appear more than once, only the first one so appearing is determinative.

Incomplete proposal

Lacks link to a spec

page-version

Pages may be revised several times daily. While date-time given to a granularity of a fraction of a second would often suffice, when a page has to be approved more than once before posting, any or no such time may be correct (without this keyword, a comment could be necessary but probably not parsable by an engine). In addition, versions regardless of date may show consecutiveness and can replace a date that must be vague. In that case, a version number may be more useful for searches and so a robot-parsable format is needed.The keyword's value is stated in ASCII digits, is any nonnegative base-10 rational number expressed as an integer or a decimal, with any number of decimal places allowed, and may be padded with any number of leading zeros to support extraction for ASCII sorting.Should this keyword appear more than once, only the first one so appearing is determinative.The versions 0 and 0.n, with n being to any number of places, signify beta versions, i.e., drafts, in the tradition of beta software, while versions 1 and higher ordinarily signify final-release versions. After a final-release version is released, a draft of a later version is not given a version number of 0 or 0.n, but is numbered higher than the last final-release version. It is suggested to page authors that draft status, if applicable, be shown in the visibly displayed text of the page, rather than that this meta tag be relied upon as the sole notice of draft status, as it may be inadequate notice if alone.To assign a low page-version such as 0.n or 1, the page's URL, if static, may be used as the relevant premise. Thus, if a page is copied or moved to a new URL, the author may choose to restart page-version numbering from 0.n or 1. If a page's URL is dynamic, e.g., if created on the fly from a script, the page author may prefer to use as the relevant premise for assigning a low page-version such as 0.n or 1 the URL of the script or other technology that generates the dynamic-URL page, placing this meta element containing this attribute within the script or other technology, not within the generating page's head element (the generating page's head element may have its own meta element with this attribute describing the generating page). If one page containing the script or other technology that generates another page has more than one means for generating dynamic-URL pages, each means should contain its own meta element with this attribute. Page-version is thus largely independent of the page's date, although both would likely advance roughly in parallel.

Incomplete proposal

Lacks link to a spec

resolutions

Authoring web sites to use resolution independent images that display beautifully on high-resolution displays should be made as easy as possible for developers and should not require JavaScript to accomplish.

To accomplish this, I propose a new HTML Meta Tag, resolutions, that can be used to specify that high-resolution versions of images linked to from the page are available and that the browser should use them in place of the lower-resolution default images if it detects that a user is using a high-resolution screen. The resolutions meta tag lists the device-pixel ratios supported by images in the page.

So, for example…

<meta name="resolutions" content="2x">

… means that the developer is telling the browser that she has created 2x resolution images for the images linked to from the current page and named them with a @2x suffix.

To illustrate, if her image tag is as follows…

<img src="/images/flower.jpg" alt="A flower">

… then she has two image files under /images: the low-resolution default (flower.jpg), and a higher-resolution (200%) version named flower@2x.jpg.

(This is the same naming convention already used by Apple in its Cocoa Touch framework for automatically loading in higher-resolution versions of images.)

Based on the meta tag, if the browser detects that the user is running at a min-device-pixel-ratio of 2.0, it will automatically ask for the 2x version of the image (flower@2x.jpg) instead of the default image as specified in the image tag.

Finally, so as not to flood external sites with high-resolution image requests, this functionality would only work for local images specified via relative links.

Multiple resolutions

The resolutions tag can also contain a list of supported device-pixel ratios so as to support even higher-resolution displays when and if they become available in the future.

For example:

<meta name="resolutions" content="2x, 4x, 8x">

In this case, the developer would provide 2x, 4x, and 8x versions of all images. So, in the running example, she would make flower.jpg, flower@2x.jpg, flower@4x.jpg, and flower@8x.jpg.

Advantages

The advantages of this approach are several:

Makes it very simple for developers to support high-resolution displays like the iPhone 4's Retina screen

Does not require JavaScript

Does not change the default way that things work (if the meta tag is not specified, the browser simply behaves as it always has).

To classify by subject a page's content, a standard subject taxonomy that will be recognized by a search engine or directory will help. Because many such high-quality taxonomies exist, only a prefix is proposed. Over time, particular taxonomies, in print or online, may be recognized here and keywords assigned for each.The keyword will be constructed case-insensitively with subkeywords in the form subj-[nationAbbrev]-[taxonomy]-[edition][-optionalSubedition], e.g., subj-US-MeSH-2009online (perhaps). After "subj-", the second subkeyword will identify the nation where the taxonomy is published or offered as an aid in identifying the taxonomy and does not limit the subject coverage; e.g., a taxonomy published in Japan may be ideal for classifying Canadian botany or Peruvian economy.As subject values may vary between editions of one taxonomy, an edition and optionally a subedition is to be identified in the third and optionally the fourth subkeywords. The subedition, if any, is any update or revision occurring between editions, such that a value drawn from that edition and subedition is stable. The means of identifying edition and subedition should be included in the registration of a keyword.Examples of taxonomies from the U.S. include MeSH (medical) and the Library of Congress Subject Headings.The value identifying a subject for a Web page will be drawn from the cited taxonomy's edition and subedition.If the value should have a style to prevent ambiguity in interpretation, that style is to be registered here for that keyword. Multiple values are expressed with multiple meta elements, one value for each, since comma-separation is probably not compatible with all taxonomies.If a value requires case-sensitivity to prevent confusion, the entry here registering the keyword must accommodate that need with the needs of HTML 5 with an appropriate rule. To that end, a proposal to allow case-sensitivity in meta tags under some circumstances has been offered in the W3C bug reporting system.

Microsoft introduced into Internet Explorer 6 Beta a feature that some website designers wished to preclude from applying in order to prevent public misunderstanding of their websites. The feature allowed a browser to add information but at a risk that users wouldn't know that it wasn't supplied by the website. This keyword was provided by Microsoft for those of us who wanted it.

Its value was "TRUE". Microsoft spelled the keyword with some capitals (Google accepts all lower-case) and the value in all capitals but whether capitalization was required for either is unknown; some opinions vary. Since it need be understood by only one browser, and that one a beta version, full standards compliance should not be assumed, and original case may be required.

Microsoft has apparently removed this instruction from its website on the ground that the beta version is no longer available and is not supported, but that doesn't assure that some users aren't still using the beta browser, perhaps inadvertently. Therefore, designers may wish to continue using the keyword and value and they are preserved here.

Lacks spec, potentially never minted by MS as a meta name (as opposed to a http-equiv value), even if minted by Microsoft, abandoned before shipping in any final release of IE

Failed Proposals

Keyword

Brief description

Link to more details

Synonyms

Status

cache

This doesn't actually work; use HTTP headers instead.Value must be "public", "private", or "no-cache". Intended as a simple way to tell user agents whether to store a copy of the document or not. An alternate for HTTP/1.1's cache-control; for publishers without access to modifying cache-control.

none

Unendorsed

no-email-collection

HTML5 prohibits URL-valued meta names. They should be rel keywords instead.Intended to reference legal policy of web site indicating that harvesting of e-mail addresses on the site is not permitted and in violation of applicable laws such as the CAN-SPAM Act of 2003.